Center punch



Oct. 4, 1955 A. JOHNSON 2,719,364

CENTER PUNCH Filed May 13, 1952 Aaron Johnson INVENTOR.

United States Patent cc CENTER PUNCH Aaron Johnson, Owensboro, Ky.

Application May 13, 1952, Serial No. 287,552

1 Claim. (Cl. 33-189) The present invention relates to new and useful improvements in center punches for use in locating and marking the center of pipes and other cylindrical work.

An important object of the invention is to provide vertical and horizontal spirit levels for the center punch whereby the tool may be used perpendicularly either on top of or under the work or horizontally at either the right or left side of the work.

Another object is to provide a tool of this character of simple and practical construction which is etficient and reliable in operation, relatively inexpensive to manufacture, and otherwise well adapted for the purpose for which the same is intended.

Other objects and advantages reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure l is a side elevational view;

Figure 2 is an enlarged vertical sectional view;

Figure 3 is a top plan view;

Figure 4 is an enlarged fragmentary vertical sectional view taken on a line 4-4 of Figure 1; and

Figure 5 is a perspective view of the supporting block or bracket for the horizontal spirit levels.

Referring now to the drawing in detail, wherein, for the purpose of illustration, I have disclosed a preferred embodiment of my invention, the numeral 5 designates a barrel having a base 6 at its lower end and composed of an internally threaded nipple 7 in which the lower end of the barrel is threaded, and a pair of diverging legs 8 integrally formed with the nipple.

A vertical bore 9 is drilled in the base 6 at the crotch portion of the legs and in which the lower end of a punch 10 is slidable. The punch is centered in the barrel and is slidable at its upper end in a central opening 11 in a cap 12 threaded on the upper end of the barrel and above which the punch extends. A coil spring 13 is held compressed in the barrel by a collar 14 secured to the punch by a set screw 15 to project the pointed lower end 16 of the punch below the lower ends of legs 8, the collar striking the base of nipple 7 to limit the downward movement of the punch.

A pair of spirit level tubes 17 are attached in a vertical position to diametrically opposite sides of the barrel 5 by holders designated generally at 18 and which are constructed of tubes 19 held in upper and lower caps 20 formed with flanges 21 which are attached to the sides of the barrel by screws 22. Windows 19a are formed in the tubes 19.

A semi-cylindrical block or bracket 23 is secured to barrel 5 below the vertical spirit levels 17 by a counter- 2,719,364 Patented Oct. 4, 1955 sunk screw 24 having a recess 25 in its head 26 and the block or bracket 23 is formed with a horizontal dovetail rib 27 adapted to enter a dovetail groove 28 in a substantially rectangular shaped spirit level tube holder 29 and which is secured in position on the block or bracket 23 by a screw 30 which enters the recess 25 of screw 24 to lock the holder 29 from sliding movement.

Upper and lower horizontal bores 31 and 32 are formed in holder 29 adjacent the upper and lower edges thereof with at least one end of each bore open and in which horizontal spirit level tubes 33 and 34 are held by plugs 35 threaded in one or both open ends of the bores. Windows 36 and 37 are formed in the upper and lower edges of the holder 29 for the spirit level tubes.

In the operation of the tool, the marking point 16 at the lower end of punch 10 is pressed against the surface of work 38 and barrel 5 is forced downwardly to rest legs 8 on the work. The tool may be placed either on top of or at the underside of the Work and the uppermost horizontal spirit level 33 or 34 checked so that the barrel 5 will be held perpendicularly and the punch is then struck a hammer blow to mark the work.

The tool may also be placed against either side of the work and the uppermost spirit level tube 17 checked to indicate the horizontal position of the barrel.

In view of the foregoing description taken in conjunction with the accompanying drawings, it is believed that a clear understanding of the device will be quite apparent to those skilled in this art. A more detailed description is accordingly deemed unnecessary.

It is to be understood, however, that even though there is herein shown and described a preferred embodiment of the invention, the same is susceptible to certain changes fully comprehended by the spirit of the invention as herein described and within the scopeof the appended claim.

Having described the invention, what is claimed as new is:

A barrel having a pair of diverging supporting legs on one end thereof, and adapted to contain a punch and to support a pair of longitudinally extending spirit level tubes spaced from said end of the barrel, a rectangular support adjacent said end of the barrel having a concave side fitting against said barrel and a dovetail rib thereon transverse to said barrel, a socket head screw securing said support to and centering the same on said barrel, a rectangular dovetail grooved block slidable on said rib and having laterally spaced parallel bores therein transverse to said barrel, a pair of spirit level tubes in said bores, plugs in the ends of said bores removable retaining said second pair of tubes in the bores, windows in said block for viewing said second pair of tubes, and a center screw in said block engageable in the socket head for centering the block and said second spirit level tubes relative to said barrel.

References Cited in the file of this patent UNITED STATES PATENTS 742,077 Sovelius Oct. 20, 1903 746,070 Gillncr et al. Dec. 8, 1903 1,213,020 Roeske Jan. 16, 1917 1,740,597 Hoyer Dec. 24, 1929 2,418,956 Silver Apr. 15, 1947 2,468,215 Leiger Apr. 26, 1949 2,587,516 Parker Feb. 26, 1952 

